How Do Low-Literacy Populations Perceive "Dirty Bombs"? Implications for Preparedness Messages

Potential terror events such as "dirty bombs" could have significant public health effects, but little is known about how low-literacy populations perceive dirty bombs, their trust in public health or government officials to provide credible information, and their willingness to comply with recommended actions. We surveyed 50 low-literacy adults from a large urban center; they were mostly members of ethnic minority groups. We used unique social marketing methods-perceptual mapping and vector message modeling-to create 3-dimensional models that reflected respondents' knowledge of what a dirty bomb is, their intended behaviors should one occur, and their concerns about complying with "shelter in place" recommendations. To further understand individual variations in this at-risk group, a k-means cluster analysis was used to identify 3 distinct segments, differing on trust of local authorities and their emergency response, willingness to comply with emergency directives, and trust of information sources. Message strategies targeting each segment were developed to focus on concepts important to moving the groups toward a "shelter in place" behavior, revealing key differences in how best to communicate with risk communication. We discuss how these methods helped elucidate specific differences in each segment's understanding of and likely response during the event of a "dirty bomb" and how these techniques can be used to create more effective message strategies targeted to these groups.